Acute and subacute encephalopathies: deficiency states (nutritional).

Optimal functioning of the central and peripheral nervous system is dependent on a constant supply of essential nutrients. Nutritional deficiencies of thiamine and niacin, rarely vitamin B (12), and possibly folate can cause a wide range of neuropsychiatric manifestations. Neurologic manifestations associated with these deficiency states are the focus of this review. The preventable and potentially treatable nature of these disorders makes this an important subject. Prognosis depends on prompt recognition and institution of appropriate therapy.